(CNN) -- Venus Williams is through to the final of the Dubai Open after defeating younger sister Serena in a three-set thriller on Friday.

Venus took a 10-9 career lead over Serena after defeating her younger sibling in the Dubai Open semifinals.

Sixth seed and Wimbledon champion Venus beat the world No.1 6-1 2-6 7-6 to take a 10-9 lead in competitive matches between the two siblings.

Serena made an awful start, hitting six double-faults in the first set and dropping her serve three times -- while Venus won all of her service games without the loss of a point.

And, despite losing the second set, Venus always looked on course to beat Serena for the fifth time in their last seven meetings when the knee problem which caused Serena to pull out of the Paris semifinals last week appeared to gradually get worse.

But, despite that handicap, the Australian Open champion took her older sister to a third set tie-break, only the second time a set has gone all the way in their 19 career meetings.

"It was definitely a finals-quality match," Venus, who has returned to the top five for the first time since August 2003, told the tournament's official Web site.

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"Obviously winning a match that close is satisfying, especially against the top-ranked player. Of course when I walk onto the court with Serena I have respect for her, so that's obviously the best part about winning," added Venus.

For her part, Serena refused to blame her troublesome knee for her defeat. "I thought Venus]played well. I didn't serve that well and I thought she served really well which I think ultimately helped her win the match," said Serena.

American Venus is now the hot favorite to beat Virginie Razzano in Saturday's final after the Frenchwoman took just over an hour to beat 16th seed Kaia Kanepi of Estonia 6-1 6-2 in the other semifinal.

It has been a dream run to the final for unseeded Razzano, who also accounted for world number two Dinara Safina and fifth seed Vera Zvonareva prior to Friday's last four showdown.

Razzano took the final four games for the loss of just three points to reach her first final since late 2007. "I didn't want to give her and chances," Razzano told the official tournament Web site.

"I wanted to be the boss today and it worked. To beat me, Kaia had to play better than me but she didn't," added Razzano.